Production of an EBS Device (Electron Beam Semiconductor Device) with cold cathode instead of conventional hot cathode has hitherto been considered impractical. It had been experienced that a cold cathode in such conditions would rapidly be poisoned by its environment. This was due to inability to maintain sufficiently high to very high vacuua (from 10.sup.-7 Torr to 10.sup.-8 Torr) within the vacuum tube. This vacuum problem is due to degassing of the interior components of the device, and the very walls of the vacuum envelope itself in such very high vaccua. Once poisoned by such atmosphere, the energy required for sustained emission of cold cathode, given by the emission equation, increases drastically; before long the cold cathode is entirely inoperational. The life span of such a device would be quite short as a result so as to render it impractical. The conventional hot cathode EBS device itself only has a maximum life span of some 20,000 hours. Avoiding the necessity of attaching appendage pumps to maintain a vacuum and numerous other inherent failure mechanisms would also be greatly desirable. To date, however, the hot cathode type EBS amplifier has been the only real choice known.
Development of a cold-cathode EBS device would be of obvious great advantage. The life-span of such a solid-state device would theoretically be unlimited; a cold cathode device would operate at room temperature, which would eliminate the requirement of a filament power supply. A cold cathode device would be lighter weight, making it thereby ideally suited for airborne and space applications.
In solving the vacuum problem, the appendage pumps needed for the conventional hot cathode device would be eliminated as well. This last simplification would even further lower the costs of production and operation which reduction would be possible because of the above cited advantages.